Well, we used to be on Aruba for 7-8 years. We got rid of it because support was horrendous. We recently made the switch to Extreme Wireless, and we couldn't have been more happier with the switch. GTAC Support has been great so far as well!

from the feature set I wouldn't use the Express one. Mostly this solution have enough features, but you can't extend it. The Instant APs have maybe comparable features, but you can extend it with AirWave or a controller and a firmware update. This is with the Express not possible.